1. Field of the Invention
The present invention relates to a stock preparation system for preparing a fiber suspension for use in a paper-making machine, and, more particularly, to a pulper in such a stock preparation system.
2. Description of the Related Art
A fiber stock preparation system is used to make a fiber suspension from a source of fiber such as wood. The fiber stock preparation system receives the raw source of fiber, breaks the raw source of fiber into individual fibers suspended within a liquid such as water, and separates contaminants from the fiber suspension.
It is known to provide a pulper in a fiber stock preparation system as described above to break down the raw source of fiber into individual fibers. A pulper typically includes a rotatable element therein which imparts mechanical forces to the source of fiber and breaks the source of fiber into individual fibers. The pulped fiber is transported downstream to other mechanical devices within the stock preparation system. For example, the pulped fiber may be further processed within a disperger. A disperger receives the pulped fiber and removes contaminants from the fiber suspension and thoroughly mix chemicals within the fiber suspension. The disperger includes a shaft assembly with a plurality of foils which move in very close proximity relative to a plurality of foils carried by a housing. The tight tolerances within the disperger are intended to process the liquid under relatively high pressure so that the chemicals may be thoroughly mixed and the contaminants removed. To achieve thorough mixing of the chemicals, the dwell time of the fiber suspension within the disperger is relatively long. The disperger has an output which is in the form of an open end of the housing which discharges directly to the ambient environment. Because of the tight tolerances and pressures utilized within the disperger, a high energy input is required to drive a disperger. Moreover, such a disperger has a low throughput rate.
What is needed in the art is a pulper which has a high throughput rate, may be oriented in multiple orientations and requires very little input energy for pulping of the input source of fiber.